Phencyclidine is a recreational drug that was marketed in the 1950s as an anesthetic pharmaceutical drug. It was taken off the market due to its dissociative hallucinogenic side effects. It began to appear as a drug of abuse in major American cities in 1967, called PCP, two years after it was banned. It still has limited use in veterinary practice. Although abuse of PCP has declined over the years, it is still considered a major drug of abuse because of the intensity of its effects and the potential for overdose in its illegal form. PCP has a history of causing hallucinations, paranoia, and extreme violent and self-destructive behavior in users. Abuse is a particular problem for law enforcement since the analgesic effect makes violent abusers highly resistant or impervious to pain when under the influence, so they are difficult for police to control.